The present invention relates generally to the field of cranes and other lifting machines designed to raise, lower, load, unload, or otherwise move cargo, materials, and other items. More specifically the present invention relates to an anti-two block system for use with a crane assembly.
A crane typically includes a main body or platform and a boom extending from the main body. The main body may be fixed or mobile. The boom supports a cable, which may be formed from metal wire, chains, rope, or other materials. A hoist or winch is used to wind and unwind the cable. The crane further includes a hook or other tool hanging from the end of the boom opposite to the main body by the cable. The hook is generally used to attach cargo, materials, or other items to the cable of the crane.
The sizes, loads, and forms of crane assemblies vary widely. In some cases, a boom includes stages of extensions that slide telescopically from one another. The number of stages varies, and may include a main section with two or more extensions. In other cases, the boom includes a jib pivotally fastened to an end of the boom, to increase the length of the boom. The jib may also include telescoping sections. In still other cases, the boom extends from the main body of the crane by way of an articulated arm that maneuvers the boom.